This invention relates to magnetic tape recording heads, and more particularly, to a tape recording head having a pre-recessed gap region filled with an electrical insulation material.
In magnetic storage systems, data is read from and written onto magnetic recording media utilizing magnetic transducers commonly referred to as magnetic heads. Data is written on the magnetic recording media by moving a magnetic recording head to a position over the media where the data is to be stored. The magnetic recording head then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read head and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media.
An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has lead to increasing the track density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head assembly for use in such systems.
In a tape drive system, magnetic tape is moved over the surface of the tape head at high speed. This movement generally entrains a film of air between the head and tape. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial so that the recording gaps of the transducers, which are the source of the magnetic recording flux, are in intimate or near contact with the tape to effect efficient signal transfer, and so that the read element is in intimate or near contact with the tape to provide effective coupling of the magnetic field from the tape to the read element.
A flat contour thin film tape recording head for a bi-directional tape drive is described in commonly assigned U.S. Pat. No. 5,905,613 to Biskeborn and Eaton. The flat contour head comprises a flat tape support surface on a substrate having a row of thin film transducers formed on a surface on one side of the substrate which forms a gap. The substrate with the row of transducers is called a “rowbar substrate”. The transducers are protected by a closure of the same or similar ceramic as the substrate. For a read-while-write bi-directional head which requires that the read transducer follows behind the write transducer, two rowbar substrates with closures are mounted in a carrier opposing one another. The recording tape overwraps the corners of both substrates and closures with an angle sufficient to scrape (skive) the air from the surface of the tape and not so large as to allow air to reenter between the tape and the tape support surface after the tape passes the corner. By scraping the air from the surface of the moving tape, a vacuum forms between the tape and the flat tape support surface holding the tape in contact with the tape support surface. At the corners of the air skiving edge, bending of the recording tape due to the overwrap results in separation of the tape from the tape support surface for a distance that depends on the wrap angle, the tape thickness and the tape tension. The transducers must be spaced from the corners of the air skiving edges at a sufficient distance to allow the pressure difference between ambient air and the vacuum between the tape and the tape support surface to overcome this separation.
Recession of the gap region between the hard ceramic substrate and closure due to tape wear is a problem that results in increased spacing loss of the readback signal. Efforts to minimize gap erosion in hard disk drive type ceramic tape heads usually involves making the gap materials more wear resistant or coating the head with wear resistant material. Another problem that can occur is accumulation of conductive debris and wear material in the recessed region that results in electrical shorting of the magnetoresistive (MR) transducer elements in the gap to other electrically conductive elements in the gap. Yet another problem is corrosion of giant magnetoresistive (GMR) or magnetic tunnel junction (MTJ) sensors when exposed directly to running tape.
The present invention addresses the need for a tape recording head that eliminates or reduces the harmful effects of accumulated conductive debris to improve reliability and component life and that insulates anisotropic magnetoresistive (AMR), GMR and MTJ sensors from electrical charge exchange with the tape.